The turbulent flow of surfactant solution in the wide‐rib rectangular grooved channels was studied by direct numerical simulation. Moreover, the variations of near‐wall streamwise vortices with time were discussed and the distributions of streamwise vortex radius, swirling strength and density were quantitatively investigated. It was found that the influence of microgrooves on the fluid mainly occurred within the buffer layer and microgrooves could induce numerous streamwise vortices with small size and swirling strength within the grooved valleys. The drag‐reducing enhancement mechanism of microgroove in the surfactant solution could be mainly considered as the competing results between the “restriction effect” and “tip effect” of microgroove, and the essential factor should be the numerous secondary streamwise vortices with small size and swirling strength within the grooved valleys. Furthermore, a predicted method for the optimal drag‐reducing size of microgroove was proposed, and the prediction values agreed well with the numerical results. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2898–2912, 2018

中文翻译：

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表面活性剂溶液在宽肋矩形沟槽通道中流动的直接数值模拟

通过直接数值模拟研究了表面活性剂溶液在宽肋矩形槽形通道中的湍流。此外，讨论了近壁流涡旋随时间的变化，并定量研究了流涡旋半径，旋流强度和密度的分布。发现微槽对流体的影响主要发生在缓冲层内，并且微槽可以在沟槽谷内引起许多具有小尺寸和涡旋强度的流向涡流。表面活性剂溶液中微沟槽的减阻增强机理主要可以看作是微沟槽的“限制效应”和“尖端效应”之间的竞争结果，关键因素应该是在沟谷内具有小尺寸和涡旋强度的众多次生涡流。此外，提出了一种最佳的微沟槽减阻尺寸的预测方法，该预测值与数值结果吻合得很好。©2018美国化学工程师学会AIChE J，64：2898–2912，2018